World Water Day: Mapping the spread of dams in the US

World Water Day was celebrated this past Sunday bringing attention to issues around water and sustainable development. Given current water use, the UN predicts the world will face a 40% shortfall in water by 2030. Recent news on California’s on-going drought, and the environmental risk posed by hundreds of dams in the US highlight the importance of water in our lives.

Much of American history, both geological and cultural, is linked to the rivers of the nation. Dams, as barriers to river flow, fit into the fabric of that narrative. There are over 80,000 dams in the US, many of them built in the early 1900s. The following map animates the construction of more than 7,000 major dams using data provided by the U.S. Geological Survey.

Impact: Energy and Environmental Factors

Around the world, hydropower generates 16% of global electricity production. In the next two years, 3,700 major dams are expected to come online, doubling the total electricity capacity of hydropower.

While hydropower can be a source of economic development, dams can also pose significant risk to the environment. Just this past week, environmental organizations including the Sierra Club published a letter to the Environmental Protection Agency on their concerns regarding the hazard risk of 900 mining dams in the United States.

Strategy: Placement and Propagation

Though the history of dams in the US has mainly involved the construction of dams, more than 200 dams have been removed since 2006. The largest dam removal project in the world was completed last August on a remote stretch of the Elwha River in Washington State, part of a growing realization that not all dams built in the US are still necessary.

Who gives a Dam?

Dams and the water flow rates they manage translate into pretty powerful political capital. The success and strategic location of dam programs control the flow of water into a landscape, influencing and propagating floods, contributing to ecological devastation, and impacting the sustanence of fish and plant species, all of which grossly affect taxepayer subsidy payments.

At the same time, water policy suffers from non-standard auditing and regulation across states. Environmental and economic disasters predicated on mismanaged dams remain a fairly persistant part of domestic policy issues. Dam safety ratings, inspection plans, affliliated hazardous conditions and the overall cost of repairs and maintenance have been the topic of several news publications and FOIA requests in the domestic U.S.

The following map uses data from the National Inventory of Dams database maintained by the U.S. Army Corps of Engineers through the year 2005 (after which continued updates were promised on a two-year basis). The data provides information about the location, name, affected rivers, towns/cities in range, material composition, purpose and structural integrity of dams in the U.S. The map below color-codes the dams by their “hazard potential,” where:

  • “low” implies non-significant risk to the environment or third parties, only to the dam owner
  • “significant” implies environmental, lifeline and economic risk; typical for rural dams
  • “high” implies human life loss in addition to the risks implied in a “significant” risk scenario

If you’re further interested in the environmental impact of dam security on wildlife apart from humans, the Fish Passage Data Archive provides data on fish counts around dams. Read on for additional dam resources, and look out for our upcoming post on building narratives about rivers with Odyssey.js!

Data Sources on Dams in the US

Happy mapping!

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